Estimating mass-wasting processes in active earth slides – earth flows with time-series of High-Resolution DEMs from photogrammetry and airborne LiDAR

A Corsini,F Ronchetti,F Cervi,P Sterzai,L Borgatti,A Dahne

doi:10.5194/nhess-9-433-2009

Abstract

Abstract. This paper deals with the use of time-series of High-Resolution Digital Elevation Models (HR DEMs) obtained from photogrammetry and airborne LiDAR coupled with aerial photos, to analyse the magnitude of recently reactivated large scale earth slides – earth flows located in the northern Apennines of Italy. The landslides underwent complete reactivation between 2001 and 2006, causing civil protection emergencies. With the final aim to support hazard assessment and the planning of mitigation measures, high-resolution DEMs are used to identify, quantify and visualize depletion and accumulation in the slope resulting from the reactivation of the mass movements. This information allows to quantify mass wasting, i.e. the amount of landslide material that is wasted during reactivation events due to stream erosion along the slope and at its bottom, resulting in sediment discharge into the local fluvial system, and to assess the total volumetric magnitude of the events. By quantifying and visualising elevation changes at the slope scale, results are also a valuable support for the comprehension of geomorphological processes acting behind the evolution of the analysed landslides.

Highlights

The analysis of recent reactivation events of large scale earth slides – earth flows in the northern Apennines of Italy was carried out by means of High-Resolution Digital Elevation Models (HR DEMs), obtained with photogrammetry and airborne LiDAR
The final objective was to gain new pieces of knowledge to be used for hazard assessment and planning of mitigation measures in these case studies
Specific aims were: interpreting and quantifying processes of depletion and accumulation at the slope scale, quantifying mass wasting at the slope scale and assessing the total volumetric magnitude of the events

Summary

Introduction

High-Resolution Digital Elevation Models (HR DEMs) have proved to be useful in the analysis of landslide processes from different perspectives and at different spatial scales, including improvement of landslide inventories, susceptibility assessment and appraisal of landslide surface features (Van Westen and Lulie Getahun, 2003; McKean and Roering, 2004; Casson et al, 2005; Metternicht et al, 2005; Glenn et al, 2006; Jaboyedoff et al, 2007). The final objective was to gain new pieces of knowledge to be used for hazard assessment and planning of mitigation measures in these case studies. Specific aims were: interpreting and quantifying processes of depletion and accumulation at the slope scale, quantifying mass wasting at the slope scale (i.e. the amount of landslide material that is wasted during reactivation events due to stream erosion along the slope and at its bottom and that results in sediment discharge into the local fluvial system) and assessing the total volumetric magnitude of the events

Test sites

Differential DEMs

Findings

Valoria landslide